A radio frequency (RF) transponder system typically includes a radio frequency identification (RFID) reader and an RFID device. The system may include multiple RFID readers, multiple RFID devices, or both. The RFID device is commonly referred to as an RFID tag. The RFID device may take a number of forms including a card or a fob. Conventional operation of the RF transponder system is generally characterized by multiple operating modes including excitation, response, and read modes. The RF transponder system requires electrical power to operate in each of these modes. In particular, the RFID reader must be powered during the excitation and read modes while the RFID device must be powered during the response mode. In many RF transponder systems the RFID device is passive, that is, the RFID device lacks an internal power source or physical connection to an external power source. The passive RFID device is powered remotely by the RFID reader while the RFID device remains free of physical contact with the RFID reader. The RFID reader may be connected to an electrical power source, such as an AC power line, which powers the RFID reader. Alternatively, the RFID reader may be powered by a self-contained power source such as a small disposable or rechargeable battery. The latter enables the system designer to position the RFID reader in a remote location which lacks access to an AC power outlet. Typically, an output device that produces one or more outputs such as visual, audible, mechanical, or electrical outputs is coupled to the RF transponder system. One commonly experienced application is a security system that controls access to a building or zones within a building. Other applications also exist.